Fabrication of three-dimensional porous La-doped SrTiO₃ microspheres with enhanced visible light catalytic activity for Cr(VI) reduction

Abstract

In recent years, much effort has been focused on the development of the photocatalysts with high performance under visible light irradiation. In this paper, three-dimensional porous La-doped SrTiO₃ (LST) microspheres were prepared by a modified sol–gel method, in which the agarose gel/SrCO₃ microsphere and La₂O₃ were employed as the template and the La resource, respectively. The as-prepared LST microspheres exhibit a porous structure with a diameter of about 10 µm and a surface pore size of about 100 nm. The La element was doped into the crystal lattice of SrTiO₃ by the substitution of La³⁺ for Sr²⁺. Therefore, the absorption edge of LST samples shifts toward the visible light region, and their photocatalytic activity for the Cr(VI) reduction is enhanced under visible light. Among all LST samples, LST-0.5 (the La³⁺ doping content is 0.5 wt-%) exhibited the highest visible-light photocatalytic activity, which can reduce 84% Cr(VI) within 100 min. This LST materials may become a promising photocatalyst for the facile treatment of wastewater containing poisonous heavy metal ions.

Graphical abstract

Keywords

SrTiO₃ / La³⁺ doping / porous microsphere / visible-light photocatalysis / Cr(VI) reduction

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Acknowledgements

The authors thank the financial support from the Program of Introducing Talents of Discipline to Universities (No. B06006), the National Natural Science Foundation of China (Grant Nos. 21621004 and 21406163), the Tianjin Research Program of Application Foundation and Advanced Technology (No. 15JCQNJC10000), the National Basic Research Program of China (No. 2009CB724705), and the National Science Fund for Distinguished Young Scholars (No. 21125627).

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